Increased dopamine and its metabolites in SH-SY5Y neuroblastoma cells that express tyrosinase

Takafumi Hasegawa, Michiko Matsuzaki, Atsushi Takeda, Akio Kikuchi, Katsutoshi Furukawa, Shigeki Shibahara, Yasuto Itoyama

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Oxidized metabolites of dopamine, known as dopamine quinone derivatives, are thought to play a pivotal role in the degeneration of dopaminergic neurons. Although such quinone derivatives are usually produced via the autoxidation of catecholamines, tyrosinase, which is a key enzyme in melanin biosynthesis via the production of DOPA and subsequent molecules, may potentially accelerate the induction of catecholamine quinone derivatives by its oxidase activity. In the present study, we developed neuronal cell lines in which the expression of human tyrosinase was inducible. Overexpression of tyrosinase in cultured cell lines resulted in (i) increased intracellular dopamine content; (ii) induction of oxidase activity not only for DOPA but also for dopamine; (iii) formation of melanin pigments in cell soma; and (iv) increased intracellular reactive oxygen species. Interestingly, the expressed tyrosinase protein was initially distributed in the entire cytoplasm and then accumulated to form catecholamine-positive granular structures by 3 days after the induction. The granular structures consisted of numerous rounded, dark bodies of melanin pigments and were largely coincident with the distribution of lysosomes. This cellular model that exhibits increased dopamine production will provide a useful tool for detailed analyses of the potentially noxious effects of oxidized catecholamine metabolites.

Original languageEnglish
Pages (from-to)470-475
Number of pages6
JournalJournal of Neurochemistry
Issue number2
Publication statusPublished - 2003 Oct


  • Dopamine
  • Neuromelanin
  • Oxidative stress
  • Parkinson's disease
  • Quinone
  • Tyrosinase


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